EP3895195B1 - Fusible link, circuit arrangement and motor vehicle comprising said circuit arrangement - Google Patents

Description

The subject relates to a fuse and a circuit arrangement with a fuse. In addition, the subject relates to the use of such a safety fuse and a circuit arrangement in automotive applications, in particular a motor vehicle with such a circuit arrangement.

Conventional fuses, which are known as so-called plug-in fuses, are nowadays also used as line protection in safety-relevant applications in motor vehicles. Flat plug fuses and mini flat plug fuses are used particularly in automotive applications. With these fuses, a fusible wire is contacted via two flat terminal lugs. The flat connection lugs are clamped in a connection housing (fuse box) and can be removed and replaced with little effort. US2002/047770A1 discloses a fuse according to the preamble of claim 1.

The lack of diagnostic capability is problematic with flat plug-in fuses as well as with other fuses. However, due to the constantly growing complexity of electronic components in vehicles, the probability of malfunctions is also increasing. If a safety-relevant component is affected, a malfunction can have devastating effects, in particular people can be injured. The ISO standard IS026262 sets out guidelines for the functional safety of electrical and electronic components in motor vehicles. In order to meet these, monitoring of the components is necessary, which is not possible with conventional fuses.

The object was therefore based on the task of optimizing the monitoring of fuses.

To solve this problem, a safety fuse according to claim 1, a circuit arrangement according to claim 11 and a motor vehicle according to claim 12 are proposed.

The fuse in question has a fuse element between a first and a second connection contact. The structure of fuses is known per se. The wire cross-section and conductivity of the fusible conductor is adjusted in such a way that it melts at a certain current intensity and thus separates an electrical path between the two connection contacts. The mode of operation of a fusible conductor in a safety fuse is also known per se, so that a detailed description is dispensed with.

Objectively, it has now been recognized that monitoring the fusible conductor is problematic in conventional fuses. In order to enable the fusible conductor to be monitored, it is proposed that a connection pin be arranged on each of the first and second connection contacts. A connector pin is an electrical conductor that protrudes away from the connector contacts. A printed circuit board is placed on the connection pin. The printed circuit board is preferably soldered to the connection pins. An integrated circuit is arranged on the printed circuit board itself, with which an evaluation of measured values recorded on the fusible conductor can be carried out. In particular, the integrated circuit has an AD converter. Furthermore, sensors can be arranged on the printed circuit board, with which physical variables on the fuse, in particular the fuse element, can be picked up. For example, current, voltage and temperature sensors can be provided. Analogue output signals from such sensors can be digitized using the AD converter and then further processed on a microcontroller. The microcontroller can also be arranged on the printed circuit board.

The fuse in question makes it possible to add monitoring functions to a conventional structure.

The fuse in question makes it possible to detect faults in the fuse. It is also possible to establish before an error occurs that an error is probable. By comparing the measured data with reference data, it is possible to determine the amount by which a measured value deviates from a target value. A deviation can be interpreted as an indication of a future possible error. Such monitoring of components is also known as preventive maintenance.

According to one exemplary embodiment, it is proposed that the printed circuit board be placed on the connection pins via vias. The printed circuit board has vias (holes) that are connected to conductor tracks on one or both sides of the printed circuit board. The printed circuit board is plugged onto the connection pins via the vias. A connection pin can be connected, in particular soldered, to the printed circuit board directly on the via, on which a soldering contact of the conductor tracks can be provided.

According to the invention, it is proposed that the integrated circuit has at least one microcontroller. The microcontroller is used to process the preferably digital measurement data. With the help of the microcontroller, it is possible to evaluate the measurement data directly at the fuse and, if necessary, to output an error signal in the event of an error or to output a warning signal if one or more measured values deviate from certain limit values.

According to one exemplary embodiment, it is proposed that an insulating layer be arranged between the fusible conductor and the printed circuit board. About these Insulation layer prevents the printed circuit board from coming into contact with the connection contacts and/or the fusible conductor.

According to one exemplary embodiment, it is proposed that the connection pins and the fusible conductor be arranged in a U-shape with respect to one another. The fuse element can form the bottom of the Us. The two legs can be formed by the connection pins. The connection pins can thus be formed protruding from the fusible conductor. The printed circuit board can be arranged between the two legs. Conventional fuse boxes allow fuses to be plugged in, making it particularly easy to replace the fuse. If a printed circuit board is additionally arranged on the fuse on the side of the fuse that faces away from the connection contacts, via the connection pins that protrude from the fuse element, it can be used in conventional fuse boxes.

The integrated circuit, in particular the microcontroller, can output wired or wireless control signals or error signals. Depending on an evaluation of the measurement signals, the integrated circuit, in particular the microcontroller, can generate an output signal which can be output in a wired or wireless manner. It is also possible for the integrated circuit, in particular the microcontroller, to couple a control signal to the connection contacts via the connection pins, which control signal can be transmitted via the vehicle electrical system to a central control device. In such a case, the safety fuse does not require any further contact to enable the measurement signals to be processed.

The integrated circuit is powered electrically via the connection pins. A voltage drop across the fusible conductor, which can also be only a few mV, is sufficient to operate the integrated circuit electrically.

According to one exemplary embodiment, it is proposed that the first and the second connection contact extend in a longitudinal axis. The longitudinal axes of the connection contacts preferably run essentially parallel to one another. The fusible conductor preferably runs essentially perpendicular to the longitudinal axes of the connection contacts. The fusible conductor and the connection contacts span a plane and the connection pins can run in this plane or essentially perpendicularly to this plane. The connection pins are primarily parallel to the respective longitudinal axes of the respective connection contacts.

According to one exemplary embodiment, it is proposed that the connection contacts are in the form of flat tabs and/or that the connection pins are in the form of wires. The connection pins are, in particular, round in the form of wires. This simplifies assembly with printed circuit boards, as these are prepared for round, wire-shaped connection pins.

According to one exemplary embodiment, it is proposed that the respective connection contacts and connection pins are formed in one piece. In a stamping-pressing process it is possible to stamp connection pins together with connection contacts. It is also possible to press the connection contacts from a wire. It is also possible for the connection pins to be soldered or welded to the connection contacts.

According to one exemplary embodiment, it is proposed that the connection contacts and the fusible conductor are arranged on a carrier substrate, that the connection pins protrude from the carrier substrate and that the printed circuit board is a component separate from the carrier substrate, but can also rest against the carrier substrate. The connection contacts and the fusible conductor are preferably arranged in a common housing. In particular, they are cast there. The connection pins are routed out of the housing. At the bottom of the housing, the connection contacts can protrude from the housing at a distance from one another. In particular, the connection contacts can be formed as flat plugs, such as This is the case with conventional blade fuses. The printed circuit board can be placed directly on the housing on the cover side of the housing, ie opposite the bottom. The connection pins can protrude from the cover of the housing and the printed circuit board can be placed on the cover. In particular, the printed circuit board is dimensioned in such a way that its surface is congruent to the cross-sectional surface of the housing parallel to the cover surface of the housing. In particular, the printed circuit board is congruent with the top surface of the housing. This makes it possible to use physical fuses in conventional fuse holders without having to change their form factor. The base and/or cover of the housing can also be any other side walls of the housing.

According to one exemplary embodiment, it is proposed that a voltage and/or a current can be tapped off via the fusible conductor and/or a temperature on the fusible conductor on the printed circuit board via the connection pins. A voltage can be measured directly between the connection pins. A current can be measured either via a measuring resistor or, for example, contactlessly via a Hall sensor or the like. The current through the fusible conductor can also be determined from the known resistance value of the fusible conductor and the voltage tapped across it. A temperature can be recorded via a temperature sensor. In particular, the temperature sensor is on the surface of the printed circuit board that faces the fuse element side. The temperature sensor can also be arranged on the printed circuit board and can determine the temperature at a connection pin. Knowing the conductivity of the connection pin and the distance from the fuse element, a temperature of the fuse element can be derived from this. The current sensor and/or the voltage sensor can be arranged on the side of the circuit board facing away from the fusible conductor. Measurement signals from the sensors are preferably analog signals, which can first be converted into digital signals by means of an AD converter in order to then be processed in an integrated circuit, in particular a microcontroller, which is also arranged in particular on the printed circuit board.

A further aspect is a circuit arrangement with a previously described safety fuse. Such a circuit arrangement is arranged in particular in a motor vehicle and is used to connect a battery to a consumer. The fuse can be arranged in the current path between the battery and the load, in particular in a fuse box. During operation, the operating current flows through the safety fuse. If an error occurs on the part of the consumer, the current exceeds a limit value and the fusible conductor melts, so that the connection between the battery and the consumer is broken. A heating of the fusible conductor and an interruption of the fusible conductor can be detected via the circuit arrangement, in particular the sensors on the printed circuit board. An increase in a current and/or a temperature can also be detected even before melting and, if necessary, preventive measures can be taken.

Fig. 1

eine Schaltungsanordnung einer Schmelzsicherung;

Fig. 2

einen Aufbau einer Schmelzsicherung in einem Querschnitt;

Fig. 3

den Einbau einer Schmelzsicherung in einen Sicherungshalter.

The object is explained in more detail below with reference to a drawing showing exemplary embodiments. Show in the drawing:

1

circuitry of a fuse;

2

a structure of a fuse in a cross section;

3

the installation of a fuse in a fuse holder.

1 shows a safety fuse 2 in an on-board network 4 of a motor vehicle. The fuse 2 is arranged between a battery 6 and a consumer 8 . The battery 6 can either be a battery for conventional consumers or a traction battery. Consumers 8 can be safety-critical consumers, such as power steering, brake power assistance, ESP, airbag control and the like. Consumer 8 can also be a drive train. The circuit arrangement 2 is arranged between the battery 6 and the consumer 8 .

A fuse 2 is in the 2 described in more detail. The safety fuse 2 has two connection contacts 12, which are preferably formed as flat plugs and which lie in one plane with respect to one another. The connection contacts 12 are electrically connected to one another via a fusible conductor 14 . The conductivity of the fusible conductor 14 is reduced compared to the conductivity of the connection contacts 12 . This can be achieved by a suitable choice of material and/or a suitable reduction in cross-section. Due to the reduction in conductivity, the fusible conductor 14 melts in the event of an overcurrent, which is well known per se.

Starting from the connection contacts 12, a connection pin 16 extends parallel to the respective longitudinal axis 12a of the connection contacts 12. The connection pins 16 can be arranged in one piece on the connection contacts 12 or attached to them, in particular welded or soldered.

The connection pins 16 are spaced apart from one another. A circuit board 18 has through-holes, so-called vias 20, at the same distance. Conductor tracks (not shown) are arranged in a conventional manner on the printed circuit board 18, via which discrete components 22, microcontroller 24, AD converter 26 and measuring sensors 28a, b can be connected to one another.

A temperature sensor 28a, for example, can be arranged on a side of the printed circuit board 18 facing the fusible conductor 14. A voltage and/or current sensor 28b can be arranged on the opposite side. During operation, the printed circuit board 18 with its components 22-28 is electrically contacted with the connection contacts 12 via the connection pins 16. A voltage as well as a current across the fusible conductor 14 can be measured with corresponding current/voltage sensors 28b. A temperature at the fuse element 14 can be measured with the sensor 28a.

Measured values can be in analog form, which are converted by the AD converter 26 and can then be further processed with the microcontroller 24 .

The safety fuse 2 is preferably constructed in such a way that parts of the connection contacts 12 , the fuse element 14 and preferably also parts of the connection pins 16 are applied to a carrier substrate 30 . The carrier substrate 30 can, for example, be a non-conductive layer, for example a so-called prepreg.

The fuse 2 has a housing 32 which encloses parts of the connection contacts 12 , parts of the connection pins 16 , the fusible conductor 14 and the carrier material 30 . The housing 32 has a housing cover 32a and a housing base 32b. The housing may be closed and the top 32a and base 32b may be an integral part of the housing 32 and not removable from the housing 32. In particular, the housing 32 cannot be opened.

The connection contacts 12 protrude from the housing 32 on the side of the housing base 32 . On the opposite side, on the housing cover 32a, the connection pins 16 protrude from the housing 32.

The fuse 2 is formed in particular as a flat plug fuse, so they are as in the 3 shown in a conventional application.

3 FIG. 12 shows an exploded drawing in which a fuse box 34 is shown. A safety fuse 2 with its connection pins 12 can be electrically plugged into the fuse box 34 . The connection pins 16 protrude from the housing 32 on the side of the housing cover 32a. The printed circuit board 18 can be plugged onto the connection pins 16 and make electrical contact with the connection pins 16 . The printed circuit board 18 can have such a form factor that its base area is essentially congruent with the area of the housing cover 32a. Thus disturbs the Circuit board 18 not even if the fuse 32 is plugged into a conventional fuse box 34.

Reference List

2

fuse

4

electrical system

6

battery

8th

consumer

12

connection contact

12a

longitudinal axis

14

fusible conductor

16

connection pin

18

circuit board

20

vias

22

discrete components

24

microcontroller

26

AD converter

28

measurement sensors

28a

temperature sensor

28b

Current/Voltage Sensor

30

carrier material

32

Housing

32a

housing cover

32b

caseback

34

fuse box

Claims (12)

1. Melting fuse (2) with

   - a melting wire (14) arranged between a first and a second terminal (12), wherein

   - a connecting pin (16) is arranged on each of the first and second terminals (12), and

   - a printed circuit board is placed on the connection pins (16)

   characterized in that

   - at least one integrated circuit is arranged on the printed circuit board (18) on the side facing away from the melting wire (14),

   - the integrated circuit comprises at least one microcontroller (24), and

   - the integrated circuit is electrically powered via the connection pins (16),

   wherein the integrated circuit is operated by the voltage drop across the melting wire (14).
2. Melting fuse (2) according to claim 1,
   characterized in that

   - the printed circuit board (18) is placed on the connection pins with vias (20).
3. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - an insulation layer is arranged between the melting wire (14) and the printed circuit board (16).
4. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the connection pins (16) and the melting wire (14) are arranged in a U-shape with respect to each other.
5. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the first and second terminals (12) extend along a longitudinal axis (12a), that the longitudinal axes (12a) of the terminals (12) are substantially parallel to each other, that the melting wire (14) is substantially perpendicular to the longitudinal axes (12a) of the terminals (12), and that the connection pins (16) are substantially parallel to the respective longitudinal axes (12a) of the respective terminals (12).
6. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the terminals (12) are formed as flat tabs and in that the connection pins (16) are formed in the shape of wires.
7. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the respective terminals (12) and connection pins (16) are formed in one piece.
8. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the terminals (12) and the melting wire (14) are arranged on a substrate, that the connection pins (16) protrude from the substrate, and that the printed circuit board (18) is separated from the substrate.
9. Melting fuse (2) according to one of the preceding claims,
   characterized in that

   - the terminals (12) and the melting wire (14) are arranged in a common housing (32), in particular cast, and in that the connection pins (16) are guided out of the housing (32).
10. Melting fuse (2) according to one of the preceding claims,
    characterized in that

    - in that a voltage and/or a current can be tapped on the printed circuit board (18) via the connection pins (16) via the melting wire (14) and/or a temperature at the melting wire (14).
11. Circuit arrangement having a melting fuse (2) according to one of the preceding claims, a battery and at least one load, the battery being electrically connected to the melting fuse (2) via the first terminal (12), and the load being connected to the melting fuse (2) via the second terminal (12).
12. Motor vehicle comprising a circuit arrangement according to claim 11.

Images